Bonded coupling liner fabrication and installation process



March 9, 1965 e. w. KRIEG 3,172,934

BONDED COUPLING LINER FABRICATION AND INSTALLATION PROCESS Filed July 25. 1960 I0 I I4 28 24/32 l6 l2 FIG. I

FIG. 4

INVENTOR GALEN W. KRIEG BY W5. W/

ATTORNEY United States Patent 3,172,934 BONDED CUWLlNG LHIER FABRICATEON AND INSTALLATION PRGCESS Galen W. Krieg, 2631 Somerset Drive, Wichita, Kans. filed duly 25, 196i), Ser. No. 44,932 6 Claims. or. 264-263) The instant invention relates to new and useful improvements in processes or methods of making couplings or pipe joints, and more specifically pertains to a method of providing a resilient and corrosion resistant liner securely bonded within a coupling and compressively biased between coupled tubular members.

It has heretofore been proposed that a resilient gasket can be disposed within a pipe coupling and be of such size as to be squeezed or compressed axially upon the joint being made up by tightening the conventional threaded connections. It has been found, during the course of extensive field experience with piping and conduit systems handling corrosive fluids, that a coupling employing a compressed gasket in accordance with the above proposal is frequently liable to commence leaking at a rapidly worsening rate after a period of time.

Investigation has indicated that such failures were at least in many instances probably due to an initially minute leakage or migration of corrosive fluid to a position radially intermediate the gasket and the coupling and/ or to the threads between the coupling and one of the pipes joined thereby. Corrosion effected by the initial leak-age enlarges the leakage path with resultant acceleration in the rate of the deterioration of the seal.

An important aim of this invention is to provide a method of coupling or coupling treatment that will deny access of any initial leakage to surfaces the corrosion of which will result in a material rate of leakage.

A further important object of this invention is to provide a method of making a sealing construction adapted for resiliently biased sealing and which can be as axially extended as desired.

Still another purpose of the invention is to provide a method that will enable exactness in the degree of resilient bias, whereby the effectiveness of the seal can be maximized particularly in relation to an extended period of use.

Yet another aim to be specifically enumerated is to provide a method of making a coupling seal in accordance with the foregoing that will minimize fluid turbulence through the coupling, and which will reduce the deleterious effects of fluids containing abrasive solids.

An additional object of the invention is to provide a method of making a coupling that is well adapted to withstand both high and vacuum internal pressures therein without any necessity for reinforcing of the liner or gasket.

As the final purpose of the invention to be specifically mentioned is the provision of a method of coupling tubular members to meet specific dimensional requirements that can be practiced in the field at the location of contemplated use while realizing the desideratums given above.

Broadly, the method of this invention involves, in the preparation of a tubular member having an internally tapered and threaded portion at one end thereof for subsequent threaded connection to an externally tapered and threaded pipe, the improvement comprising the steps of screwing a threaded hollow barrier having an adhesion resistant face into the member to position the face at a position intermediate the axial extent of the tapered and threaded portion of the tubular member, said face having a radial extent substantially greater than the depth of the threads of said portion of the tubular member, providing a liner within the tubular member that is bonded to the 3,172,934 Patented .Mar. 9, 1965 threaded interior of said portion thereof and which liner is spaced from said end of the tubular member by providing a polymerizable elastomer, forming the elastomer into an elongated worm-like configuration, progressively applying the length of the worm-like configuration of the elastomer to and pressing the same against the barrier face and into the threads of the threaded interior of said portion of the tubular member along a travel path generally directed to circumscribe the interior of the tubular member, thereafter polymerizing and bonding said elastomer to the tubular member, and then unscrewing the barrier from the tubular member. Preferably, this aspect of the method of the invention also entails the elastomer being applied and pressed to the threaded interior of the tubular member in the aforesaid manner in successive layers to build up a liner thickness substantially greater than the depth of the threads and of a thickness approximating the radial extent of the barrier face prior to polymerizing and bonding the elastomer to the tubular member. Additionally, this aspect of the invention preferably involves the lengths of the elastomer being formed by rolling between the hands.

Another aspect of the method of the invention involves, in a method of preparing a tubular member having a tapered and internally threaded portion in one end thereof for subsequent sealing connection to an externally tapered and threaded pipe to be threaded thereinto, the improvement comprising the steps of screwing an externally threaded hollow barrier having an adhesion resistant annular face at one end thereof into the tubular member to position the annular face of the barrier intermediate the axial extent of the tapered and internally threaded portion of the tubular member and facing from said one end of the tubular member, providing a resilient and corrosion resistant liner in the tubular member that is bonded to the part of the tapered and internally threaded portion of the tubular member faced by the face of the barrier by providing a polymerizable elastomer, rolling a portion of the elastomer to an elongated shape and progressively pressing the longitudinal extent of such elongated portion of the elastomer against the inside of the tubular member adjacent the barrier and against the face of the barrier along a path directed to circumscribe the interior of the tubular member, continuing the last step until the elastomer has been built up into a layer adjacent the barrier having a thickness of about the radial extent of the barrier face and having an axial annular extremity abutting the face of the barrier, polymerizing the layer of elastomer to constitute the resilient liner and to bond the liner to the tubular member, and removing the barrier.

Still another aspect of the method of this invention involves, in a method of establishing a sealing connection between a tubular member having a tapered and internally threaded portion at one end thereof and an externally tapered and threaded pipe, said pipe when tightly threaded into the tapered and internally threaded portion of the tubular member having an end at a first position intermediate the axial extent of such portion of the tubular member, the improvement comprising the steps of screwing a hollow barrier having anannular adhesion resistant face into the tubular member to position the barrier face at a second position that is intermediate and spaced from both the first position and the end of the tubular member, providing a resilient and corrosion resistant liner in the tubular member that is bonded to the part of said portion of the tubular member that is faced by the barrier face by providing a polymerizable elastomer, rolling a portion of the elastomer to an elongated shape and progressively pressing the longitudinal extent of such elongated portion of the elastomer against the inside of the tubular member adjacent the barrier face and against the barrier face along a path directed to circumscribe the interior of the tubular member, continuing the last step until the elastorner has been built up into a layer of a thickness approximating the radial extent of the barrier face and has an annular axial extremity abutting the face of the barrier, polymerizing the layer of elastomer to constitute the resilient liner and to bond the liner to the tubular member, removing the barrier, and thereafter tightly threading the pipe into the tubular member and forcing the end of the pipe to-engage and axially compress the resilient liner and also to engage a part of the liner bonded to the tubular mem- 'ber intermediate the first and second positions radially between the tubular member and the pipe.

The invention and its best mode of practice will be best understood upon reference to the accompanying drawings illustrative of preferred embodiments thereof, wherein:

FIGURE 1 is a central longitudinal sectional view showing in use a coupling according to the invention;

FIGURE 2 is a sectional view similar to FIGURE 1 of a modification of the coupling;

FIGURE 3 is an enlarged sectional detail view of the structure shown in FIGURE 2; and,

FIGURE 4 is a central longitudinal sectional view of a coupling similar to that shown in FIGURE 1 during the making thereof, together with a tool used in fixing the length of the liner.

Referring to the drawings, the number designates generally a tubular member having opositely tapered, internally threaded end portions 12 and 14 for threaded engagement with the externally threaded and tapered end portions 16 and 18 of pipes 20 and 22, respectively. As thus far described, the structure is entirely conventional, -and the tubular member or coupling 10 is also shown at 24 as being threaded intermediate the adjacent ends of the pipes 20 and 22 as is typical of most commercially available couplings of this character.

The structure shown in FIGURE 1 includes a resilient liner designated generally at 26. The liner 26 constitutes an integral part of the coupling 10 in that the liner 26 is securely bonded to the other portion thereof. The liner '26 is securely bonded to the shoulder 28 constituted of the end of the pipe 22. Furthermore, the liner 26 is thin and feathered or tapering section overlaps the shoulder 28 or end of the pipe 22 as shown at 30, with such lip portion 30 also being firmly bonded to the pipe 22. The liner '26 is also firmly bonded to the threaded portion 24 of the tubular member 10. While the body of the coupling 10 is shown as threaded throughout the axial extent thereof between the adjacent ends of the pipes 20 and 22, 'as shown in FIGURE 1, this is by no means essential. The threading of the portion 24 is typical of commercial couplings, and while constituting a weakness for corrosion ordinarily does not do so in the practice of this invention because of the bonding. In fact, threading serves to increase the area of and strength of the bonding.

It is to be understood that as shown in FIGURE 1 that the joint' or coupling of the pipes 20 and 22 is fully made up in which instance the pipe 20 is compressively engaging and deforming the adjacent end of the liner 26 to a predetermined extent as will be more fully appreciated in the forthcoming description of the method of making and bonding the liner 26. It will sufiice for the present to explain that in repose the resilient liner 26 extends somewhat further to the right axially in the tubular member 10 than is shown in FIGURE 1 and is securely bonded to the latter throughout such extent. Thus, the end of the pipe 20 not only compressively engages and deforms the adjacent end of the liner or sleeve 26, but additionally the terminal threads on the end of the pipe 20 partially enter the spaces between threads 32 in the tubular member 10 in which the liner 26 is bonded. Thus, the compressive seal between the end of the pipe 20 and the liner 26 throughout the radial extent of their juncture (it will be noted that as made up that the internal configuration and dimensions of the liner 26 corerspondand merge smoothly with those of the pipes 20 and 22) is supplemented very greatly by the resilient material of the bonded liner 26 that is compressively gripped under substantial pressure between the partially meshing threads at the end of the pipe 20.

The coupling structure shown in FIGURE 1 is extremely resistant to leaking. This will be apparent in view of the foregoing paragraph and when the total extent of the bond between the liner 26 and the pipe 22 is considered. With respect to the overlapping portion 39 of the liner 26 it should be observed that it is not essential for the conduit system including the structure shown in FIG- URE 1 to be so arranged, it is preferred that the system be such that fluids flow from right to left as seen in FIGURE 1. This is particularly preferred when the fluids contain abrasive solids as the transition of the character of the confining walls is less abrupt and deemed less conductive to turbulence and abrasion of the pipe immediately downstream of the liner 26.

Attention is now directed to the form of the invention shown in FIGURE 2. Here the invention is shown as applied to a conventional flush, high drill joint appropriately modified as hereinafter described.

The coupling shown in FIGURE 2 comprises pipes 49 and 42 disposed in end to end relation with their adjacent ends enlarged as at 44 and 46, respectively. The pipe 42 is provided with an internal shoulder 48 and is also provided with tapered internal threads 59 that extend preferably but not necessarily all the way to the shoulder 48.

The pipe 4% terminates in an annular shoulder 52 that surrounds a reduced and tapered extension 54, that is threaded, as shown, to mate with the threads 50 of the pipe 42. When the coupling is fully made up as shown in FIGURE 2, the shoulder 52 abuts the end of the pipe 42 while the end '56 of the extension 54 terminates spaced from the shoulder 48. The threads 59, while not necessarily extending all the way to the shoulder 48, do extend at least a part of the interval between the end 56 of the pipe 42 and the shoulder 48. The structure of FIGURE 2 thus far described can be obtained from conventional piping structure by appropriate shortening of the extension 54 to that shown, it being understood that ordinarily such extension as commercially available has a length such as to engage the shoulder 48 or to terminate in very close proximity thereto.

The pipes 40 and 42 can if desired and preferably do include conventional internal protective coatings 58 and 60 such as the illustrated cement linings. Such protective coatings 58 and 60 are quite commonplace and very desirable when the pipes 49 and 42 are to be used in connection with fluids corrosive and/ or particularly abrasive to the basic material of the pipes 40 and 42. The instant invention has applicability to the pipes 40 and 42, lined or unlined with protective coatings, and the coatings or linings 58 and 69 can in the following discussion be considered as integral parts of the pipes 40 and 42. In further regard to the matter of protective coatings, it should be amply apparent to those skilled in the art that the pipes 20 and 22, though shown as being of homogeneous composition, can (like pipes 49 and 42) be of composite character so as to include such internal protective coatings or linings as may be considered expedient or desirable.

A resilient liner or gasket 62 that correspond to the previously described liner 26 is disposed in the space between the shoulder 48 and the end 56 of the pipe 40.

The liner 62 is bonded to the threads 50 and the shoulder 43 including the continuation thereof constituted of the coating 60'. In fact, the entire contacting area of the liner 62 with the bodyof all portions of the pipe 42 is bonded and voids excluded from therebetween. The liner bonded to the threads 50 throughout such greater axial extent, whereby the liner 62 is in axial compression by the pipe 49, at least in the vicinity of the end 56 thereof. Also, the terminal threads on the extension 54 compressively grip the portion of the liner 62 most remote from the shoulder 48. This latter function is analogous to the thread gripping action previously described in connection with FIGURE 1.

The functions of the form of the invention shown in FIGURE 2 will certainly not require detailed discussion for those modestly conversant in the art, especially in the light of the previous discussion of the form of the invention shown in FIGURE 1. The only elaboration deemed of value at this point is the fact that the length of the liners 26 and 62 in repose exceeds their lengths upon the making up of their respective joints or couplings by a more or less fixed amount that is relatively independent of the length of the liner when compressed in use. Such fixed amount, things other than length of the liner being constant, tends to fix the compressive force against the free end of the liner (that is the end remote from the shoulders 28 or 48) for the reason that the bonding of the entire axial extent of the liner materially reduces the extent that the liner can yield axially under compression along its length. Considering the size of the pipe and the specific character of the liner material, it is a simple matter thought to be well within the capabilities of those active in the art to select or adjust the value of the fixed amount such that no tearing away of bonded areas or any rupture or tearing of the liner will occur during making up a joint or coupling, whereby any particular coupling or joint can be repeatedly made up and torn down without any serious loss in efficiency of the joint or coupling.

Though other procedures for making the described joints or couplings will probably come readily to mind, it has been found that the hereinafter described process of making and bonding the liners results in a superior product.

While the process can of course be carried out in a central plant or factory, the process enjoys as will be seen the important advantage of being able to be carried out by a single individual in the field or at a remote location to fit any specific problem or environment, and requires a bare minimum of basic materials and tools.

For a thorough and complete understanding of the preferred process attention is directed to FIGURE 4, wherein a liner analogous to that shown at as in FIGURE 1 is shown in the course of fabrication.

In FIGURE 4, the number 70 indicates a conventional coupling having oppositely tapered, internal threads 72 and 74. Initially, the coupling is firmly and finally made up on the threaded and tapered end '76 of a pipe 78. The pipe 73 can if desired be provided with an internal protective coating; however, in any event the inside of the pipe 78 adjacent its end 8%, and the exposed inside of the coupling 70 adjacent the end 8% must be in suitable condition for bonding. Generally such conditioning will require cleaning mechanically as by using a wire brush or sand blasting, so as to remove oil or grease, rust, mill scale, loose materials and any other chemicals or contaminants that might deter the bonding or adhesion action to be obtained.

On the well-founded assumption that considerable variation particularly as to threads occurs as to the various couplings such as the one shown at 76, and with respect to the pipes to be connected by the coupling, it will be further assumed that the actual spacing between the end 86 of the pipe '78 and the end of the pipe (not shown) with which the coupling is to be made up with is known (such distance being known in the art as the back ofi area or distance), a blind or barrier designated generally at 82 is adjusted to suit the circumstances as now described.

The blind 82 comprises a tubular member 84 having a tapered and threaded end portion 86 for cooperation with the coupling threads 74, the threaded end of the tubular member 84 is provided with a radially inwardly projecting annular flange 86 having an internal diameter equal to the internal diameter of the pipe 78. The other end of the tubular member 84 is provided with a radially outward projecting flange 88 through which an axially extending adjustment screw 90 is threaded to bear against the end of the coupling 70, as shown. The screw 90 is adjusted to limit threaded penetration of the blind 82 into the coupling so that the spacing of the flange 86 from the end St) of the pipe 78 is in excess of the previously determined back off distance. This excess is on the order of from about one-eighth to three-sixteenth inch for one inch to twelve inch pipes by way of example.

Prior to positioning the blind 82 as shown in FIGURE 2, the side of the flange 86 remote from the flange 88 is conditioned to prevent or substantially reduce any adhesion or bonding action between the material of the liner and the blind 82. This is most easily accomplished by suitably coating such parts of the blind 82 as may be necessary with a substance resistant to adhesion or bonding. Suitable choice of a coating for this purpose is of course dependent upon the material selected for the liner; however, liquid silicones Work very well with most of the types of liner materials used.

Following the cleaning of the pipe '78 and the coupling '70, it is always preferred and is in fact obligatory where essential to bonding to apply a suitable primer to the areas thereof to which the liner is to adhere or be bonded. Generally, such priming is done just before the blind 82 is threaded into the coupling 70.

After the blind 82 is coated by a suitable release agent as required and positioned in the coupling 7%, and after the cleaning and priming have been completed, the liner material is positioned, shaped and bonded in position. In this operation it will be noted that with the end of the blind 82 adjacent and facing the pipe 78 constitutes a barrier, and that such barrier in combination with the end of the pipe 7 8 and the intervening internal surface of the coupling or tubular member 70 constitutes what may be termed a mold cavity. The liner can be made of various materials that are commercially available and widely distributed. Though not intending to be limited to such materials, neoprene putties can be mentioned by way of example. Preferably, a neoprene putty should have a solids content of at least about 80%, of which at least about 40% should be sulfur-modified-neoprene. The specific gravity should be from about 1.1 to about 1.4 and have a viscosity of about 8X10 to about 12 10 centipoises at 77 F. When neoprene putty is used, a low viscosity neoprene can be used as a primer for outstanding bonding action. This primer can be brushed on or sprayed to the appropriate surfaces as desired.

At an appropriate time interval prior to the application of the neoprene putty (usually as short as possible) the neoprene putty is mixed with an appropriate amount of curing or polymerizing agent (usually an alkali or alkaline earth oxide) sometimes referred to as an accelerator. Military Specification Mil-15058A gives details of a suitable neoprene material.

The condensation polymer of organic dichlorides (such as ethylene chloride) and sodium tetrasulfide such as marketed under the trademark Thiokol for example is also well suited for the practice of the invention. A typical putty of this type should have about the same physical properties as given above for neoprene putty. With a Thiokol putty, the use of a low viscosity polymer of the same character is recommended for use as a primer. Prior to use of the Thiokol putty, the same is mixed with a suitable curing or polymerizing agent such as lead peroxide.

The character of materials such as given above and their use to make molded polymerized products or coatings is well known. Other commercially available materials suitable for molding and bonding products having the class designation of elastomers are well known with others being constantly developed through research. Other well known and suitable materials are butyl rubbers, vinyl putties, epoxy resins, and urethane rubbers, though this list is far from exhaustive. Use of these and equivalent materials for the purposes of the instant invention is plainly within the capabilities of those skilled in the art.

The instant invention is not primarily concerned with nor to be limited to the use of any specific material for the liner (though neoprene and Thiokol materials are presently preferred mostly because of their resistance to petroleum oils), but is primarily concerned with and directed to the process of applying, shaping and bonding a material such as exemplified by those named above during the time that such material is polymerizing or curing to become an impervious, resilient solid or elastromer having characteristic rubber-like properties, and being resistant to attack by many common chemicals. Formation of the liner in this manner makes for a superior bond and a liner that conforms to contacting parts perfectly even when in repose.

While it may be possible to apply the material of the liner while still in a plastic state by conventional pressure type nozzles or the like with appropriate manipulation of the nozzle and/ or coupling, experience has indicated in field type operations that uniformly good results are obtained upon applying the material by hand, and such mode of application is decidely preferred.

The best mode of hand application involves keeping the surfaces wetted by ethyl alcohol or other suitable agent to prevent adherence of the material to the hands. The material is applied to the surfaces to which it is bonded and is preferably built up to its desired shape in thin layers with great care being exercised to express all air from between the coated parts and the material of the liner. It is extremely important and essential that the presence of voids be kept to a minimum. Voids if allowed to remain result in a weakness in the finished liner and frequently cause blisters on the internal surface of the liner during the setting or curing of the latter.

The thin layers of material are most conveniently applied and entrained or trapped air most easily excluded particularly from within the grooves or valleys in threaded areas if a quantity of material is worked or rolled between the hands to form a worm-like length of the same of say about two to four inches in length and then building the layer up by pressing the same into position progressively along its length in the form of a spiral or helix or part of such curve. This operation is repeated for a suflicient number of times to build up and obtain the desired final shape of the liner 92 including the lip portion 5%. The hand shaping and pressing of the liner 92 and lip 94 is continued until the material has acquired sufiicient strength to be self-supporting, and is then allowed to cure or set for a suflicient additional period as to be in condition for use. This additional interval is usually from about 24 to about 72 hours for the above described neoprene or Thiokol materials, though this interval is usually given by the manufacturer of any particular typ of raw materials that may be used. Ordinarily it is prudent to inspect the liner a time or two very early in the setting or curing period. If such early inspections indicate any flow or deformation has occurred under the influence of gravity, it is normally a simple matter to reform the shape desired and then to allow the curing period.

To avoid any serious adhesion between the liner and the blind 82, the latter is preferably removed as soon as it is ascertained with certainty that the liner 92 and its lip will permanently retain their desired configuration.

A preferred refinement in the configuration of the internal surface of the liner 92 is that the same has a concaved surface such as to become essentially cylindrical during the compression thereof occasioned by making up the coupling or joint. This configuration is similar in some respects to that of the gasket disclosed in US. Patent No. 2,805,872 entitled Lined Pipe Coupling With Internally Flush Gasket issued to B. I. Routh, September 10, 1957. Contrary to the patented gasket, which is uniformly concaved throughout nearly its entire length, the liner of this invention is concaved to a progressively greater extent adjacent the free end of the liner 2 (the end remote from the lip 94). This refinement is most pronounced in longer liners and is due to the fact that axial compression of the liner 92 is a decreasing function with increasing distance from the free end thereof because of the exterior being bonded to a surface that remains essentially constant in length.

After the liner 92 and its lip 94 have cured, the coupling is made up on the other pipe (not shown) to result in a final assembly analogous to those shown in FIGURES l and 2.

While the invention has been shown with respect to pipes and fittings having metal bodies such as steel, it is to be clearly understood that the invention is applicable to any sort of pipe materials or coupling materials to which the liner can be securely bonded, such as many types of thermoplastic and thermosetting plastics (polyethylene, polyvinyl chlorides, phenolic expoxy resins, and phenolic laminates for example), glass, concrete, and various composition materials such as carbon based substance sold under the trademark Car-bate, and cement and asbestos (such as sold under the trademark Transite").

The hand application of the material of the liner is of course limited to sizes that will accommodate the hand or finger (for smaller sizes mechanical applicators, gun nozzles or the like must be resorted to); however, it will be appreciated that the structural features of the product are of value for any size of pipe or tubing.

It will be understood that both ends of the coupling 10 of FIGURE 1 can be completed using blinds, whereby each end of the liner is like the right-hand end of the same as seen in FIGURE 1. Of course, in this case each end of the liner is free in the sense that this word has been used previously. Hence, the liner will be concaved when in repose adjacent each end as is the right end of the liner shown in FIGURE 4.

The liner of the invention can have reinforcing embedded therein, as in prior art gaskets, but such provision is hardly necessary for either high or low pressures Within the coupling. Obviously, the coupling and pipe support the liner against high internal pressures. In the case of low or vacuum internal pressures, the ambient pressure cannot gain radial access to the liner so as to collapse the latter. Even if some radial access were to occur in a limited area, it is plain that adjacent bonded areas of the liner would support the unbonded limited area.

The seal afforded by the liner at its free end is due to the axial compression of the rubber-like liner coupled with the bond of the latter to the coupling. The seal at the free end is substantially augmented by the portion of the liner compressed and forced against the threads to which it is bonded and the tensile stresses within the body immediately in the vicinity, that is, from the part of the liner squeezed in the threads around the threaded extremity of the male fitting and on into the body of the liner.

Inasmuch as the apparatus and methods of the invention are each subject to numerous minor variations from the drawings and the foregoing description without departing from the spirit of the invention, attention is directed to the appended claims in order to ascertain the actual scope of the invention.

I claim:

1. In a method of preparing a tubular member having a tapered and internally threaded portion at one end thereof for subsequent sealing connection to an externally tapered and threaded pipe to be threaded thereinto, the improvement comprising screwing an externally threaded hollow barrier having an adhesion resistant annular face at one end thereof into the tubular member to position the annular face of the barrier intermediate the axial extent of the tapered and internally threaded portion of the tubular member and facing from said one end of the tubular member, providing a resilient and corrosion resistant liner in the tubular member that is bonded to the part of the tapered and internally threaded portion of the tubular member faced by the face of the barrier by providing a polymerizable elastomer, rolling a portion of the elastomer to an elongated shape and progressively pressing the longitudinal extent of such elongated portion of the elastomer against the inside of the tubular member adjacent the barrier and against the face of the barrier along a path directed to circumscribe the interior of the tubular member, continuing the last step until the elastomer has been built up into a layer adjacent the barrier having a thickness of about the radial extent of the barrier face and having an axial annular extremity abutting the face of the barrier, polymerizing the layer of elastomer to constitute the resilient liner and to bond the liner to the tubular member, and removing the barrier.

2. The method of preparing a tubular member having a tapered and internally threaded portion at one end thereof for subsequent sealing connection to an externally tapered and threaded pipe to be threaded thereinto, said tubular member being provided with an internal annular shoulder spaced from and facing toward the tapered and internally threaded portion of the tubular member; said method comprising screwing an externally threaded hollow barrier having an adhesion resistant annular face at one end thereof into the tubular member to position the annular face intermediate the axial extent of the tapered and internally threaded portion of the tubular member and facing in spaced relation toward the shoulder, Whereby the shoulder, the face and the internal surface of the tubular member therebetween define a mold cavity, providing a resilient and corrosion resistant liner in the mold cavity that is bonded to the shoulder and the interior of the tubular member intermediate such shoulder and the face of the barrier by providing a polymerizable elastomer, rolling portions of the elastomer to elongated shapes and progressively pressing the longitudinal extents of such elongated portions of the elastomer against the shoulder, the internal surface of the tubular member and the face of the barrier along paths directed generally to circumscribe the interior of the tubular member to build the elastomer up in thickness to extend as an unbroken layer of a thickness approximating the radical extent of the shoulder between the shoulder and the barrier with voids being excluded between such layer and the tubular member, polymerizing the elastomer layer to constitute the resilient liner and bond the latter to the tubular member and the shoulder, and removing the barrier.

3. In a method of establishing a sealing connection between a tubular member having a tapered and internally threaded portion at one end thereof and an externally tapered and threaded pipe, said pipe when tightly threaded into the tapered and internally threaded portion of the tubular member having an end at a first position intermediate the axial extent of such portion of the tubular member; the improvement comprising screwing a hollow barrier having an annular adhesion resistant face into the tubular member to position the barrier face at a second position that is intermediate and spaced from both the first position and the end of the tubular member, providing a resilient and corrosion resistant liner in the tubular member that is bonded to the part of said portion of the tubular member that is faced by the barrier face by providing a polymerizable elastomer, rolling a portion of the elastomer to an elongated shape and progressively pressing the longitudinal extent of such elongated portion of the elastomer against the inside of the tubular member adjacent the barrier face and against the barrier face along a path directed to circumscribe the interior of the tubular member, continuing the last step until the elastomer has been built up into a layer of a thickness approximating the radial extent of the barrier face and has an annular axial extremity abutting the face of the barrier, polymerizing the layer of elastomer to constitute the resilient liner and to bond the liner to the tubular member, removing the barrier, and thereafter tightly threading the pipe into the tubular member and forcing the end of the pipe to engage and axially compress the resilient liner and also to engage a part of the liner bonded to the tubular member intermediate the first and second positions radially between the tubular member and the pipe.

4. In a method of preparing a tubular member having an internally tapered and threaded portion at one end thereof for subsequent threaded connection to an externally tapered and threaded pipe, the improvement comprising screwing a threaded hollow barrier having an ad hesion resistant face into the member to position the face at a position intermediate the axial extent of the tapered and threaded portion of the tubular member, said face having a radial extent substantially greater than the depth of the threads of said portion of the tubular member, providing a liner within the tubular member that is bonded to the threaded interior of said portion thereof and which liner is spaced from said one end of the tubular member by providing a polymerizable elastomer, forming the elastomer into an elongated worm-like configuration, progressively applying the length of the Worm-like con figuration of the elastomer to and pressing the same against the barrier face and into the threads of the threaded interior of said portion of the tubular member along a travel path generally directed to circumscribe the interior of the tubular member, thereafter polymerizing and bonding said elastomer to the tubular member, and then unscrewing the barrier from the tubular member.

5. The method of claim 4, wherein said elastomer is applied and pressed to the threaded interior of the tubular member in the aforesaid manner in successive layers to build up a liner thickness substantially greater than the depth of the threads and of a thickness approximating the radial extent of the barrier face prior to polymerizing and bonding the elastomer to the tubular member.

6. The method of claim 5, wherein the liner is built up from a plurality of separate lengths of elastomer of said worm-like configuration, with each of such lengths being manually formed by rolling between the hands, and thereafter applied and pressed in the aforesaid manner by hand.

References Cited in the file of this patent UNITED STATES PATENTS 304,276 Nuttall Aug. 26, 1884 595,437 Greenfield Dec. 14, 1897 906,225 Harrison Dec. 8, 1908 1,334,306 Liberty Mar. 23, 1920 1,979,470 Johnston Nov. 6, 1934 2,110,053 Phillips Mar. 1, 1938 2,131,839 Hall Oct. 4, 1938 2,312,579 OBrien Mar. 2, 1943 2,340,537 Kenner Feb. 1, 1944 2,368,610 Fischer Jan. 30, 1945 2,374,138 Sanford Apr. 17, 1945 2,427,196 Cox Sept. 9, 1947 2,451,046 Rernbert Oct. 12, 1948 2,487,241 Hilton Nov. 8, 1949 2,533,885 Hill Dec, 12, 1950 2,559,806 Thompson July 10, 1951 2,677,633 Gross May 4, 1954 2,711,171 Dunnican June 21, 1955 (Other references on following page) 11' 12 UNITED STATES PATENTS 2,980,451 Taylor Apr. 18, 1961 2,770,476 Cleverly Nov. 13, 1956 3,002,770 9116511111 31 1961 2,805,872 Routh Sept. 10, 1957 2,871,036 Goodman Jan. 27, 1959 FOREIGN PATENTS 2,889,582 Cooper June 9, 1959 5 914,085 Germany June 24, 1954 2,915,322 Dunlap Dec, 1, 1959 365,375 Great Britain Jan. 21, 1932 

1. IN A METHOD OF PREPARING A TUBULAR MEMBER HAVING A TAPERED AND INTERNALLY THREADED PORTION AT ONE END THEREOF FOR SUBSEQUENT SEALING CONNECTION TO AN EXTERNALLY TAPERED AND THREADED PIPE TO BE THREADED THEREINTO; THE IMPROVEMENT COMPRISING SCREWING AN EXTERNALLY THREADED HOLLOW BARRIER HAVING AN ADHESION RESISTANT ANNULAR FACE AT ONE END THEREOF INTO THE TUBULAR MEMBER TO POSITION THEN ANNULAR FACE OF THE BARRIER INTERMEDIATE THE AXIAL EXTENT OF THE TAPERED AND INTERNALLY THREADED PORTION OF THE TUBULAR MEMBER AND FACING FROM SAID ONE END OF THE TUBULAR MEMBER, PROVIDING A RESILIENT AND CORROSION RESISTANT LINER IN THE TUBULAR MEMBER THAT IS BONDED TO THE PART OF THE TAPERED AND INTERNALLY THREADED PORTION OF THE TUBULAR MEMBER FACED BY THE FACE OF THE BARRIER BY PROVIDING A POLYMERIZABLE ELASTOMER, ROLLING A PORTION OF THE TUBULAR MEMBER FACED BY THE FACE OF THE BARRIER BY PROVIDING A POLYMERIZABLE ELASTOMER, ROLLING A PORTION OF THE ELASTOMER TO AN ELONGATED SHAPE AND PROGRESSIVELY PRESSING THE LONGITUDINAL EXTENT OF SUCH ELONGATED PORTION OF THE ELASTOMER AGAINST THE INSIDE OF THE TUBULAR MEMBER ADJACENT THE BARRIER AND AGAINST THE FACE OF THE BARRIER ALONG THE PATH DIRECTED TO CIRCUMSCRIBE THE INTERIOR OF THE TUBULAR MEMBER, CONTINUING THE LAST STEP UNTIL THE ELASTOMER HAS BEEN BUILT UP INTO A LAYER ADJACENT THE BARRIER HAVING A THICKNESS OF ABOUT THE RADIAL ETENT OF THE BARRIER FACE AND HAVING AN AXIAL ANNULAR EXTREMITY ABUTTING THE FACE OF THE BARRIER; POLYMERIZING THE LAYER OF ELASTOMER TO CONSTITUTE THE RESILIENT LINER AND TO BOND THE LINER TO THE TUBULAR MEMBER, AND REMOVING THE BARRIER. 